import { AfterViewInit, Component, ElementRef, OnInit, ViewChild } from '@angular/core';
import { MatPaginator } from '@angular/material/paginator';
import { MatSort } from '@angular/material/sort';
import { ProductListDataSource } from './product-list-datasource';
import { Product } from '../../core/product';
import { ActivatedRoute } from '@angular/router';
import { debounceTime, distinctUntilChanged, startWith } from 'rxjs/operators';
import { FormBuilder, FormGroup } from '@angular/forms';
import { Observable } from 'rxjs';
import { ToCsvService } from '../../shared/to-csv.service';

@Component({
  selector: 'app-product-list',
  templateUrl: './product-list.component.html',
  styleUrls: ['./product-list.component.css']
})
export class ProductListComponent implements OnInit, AfterViewInit {

  constructor(private route: ActivatedRoute, private fb: FormBuilder, private toCsv: ToCsvService) {
    this.showExtended = false;
    this.createForm();
    this.filter = this.listenToFilterChange();
  }

  get showExtended(): boolean {
    return this._showExtended;
  }

  set showExtended(value: boolean) {
    this._showExtended = value;
    if (value) {
      this.displayedColumns = ['name', 'costPrice', 'productYield', 'productGroup', 'info'];
    } else {
      this.displayedColumns = ['name', 'costPrice', 'productGroup', 'info'];
    }
  }
  @ViewChild('filterElement', { static: true }) filterElement: ElementRef;
  @ViewChild(MatPaginator, { static: true }) paginator: MatPaginator;
  @ViewChild(MatSort, { static: true }) sort: MatSort;
  dataSource: ProductListDataSource;
  filter: Observable<any>;
  form: FormGroup;
  list: Product[];
  /** Columns displayed in the table. Columns IDs can be added, removed, or reordered. */
  displayedColumns: string[];

  private _showExtended: boolean;

  createForm() {
    this.form = this.fb.group({
      filter: ''
    });
  }

  listenToFilterChange() {
    return this.form.get('filter').valueChanges
      .pipe(
        startWith(''),
        debounceTime(150),
        distinctUntilChanged()
      );
  }

  ngOnInit() {
    this.route.data
      .subscribe((data: { list: Product[] }) => {
        this.list = data.list;
      });
    this.dataSource = new ProductListDataSource(this.paginator, this.sort, this.filter, this.list);
  }

  ngAfterViewInit() {
    setTimeout(() => {
      this.filterElement.nativeElement.focus();
    }, 0);
  }

  exportCsv() {
    const headers = {
      Code: 'code',
      Name: 'name',
      Units: 'units',
      Fraction: 'fraction',
      FractionUnits: 'fractionUnits',
      CostPrice: 'costPrice',
      Yield: 'yield',
      ProductGroup: 'productGroup'
    };

    const csvData = new Blob([this.toCsv.toCsv(headers, this.dataSource.data)], {type: 'text/csv;charset=utf-8;'});
    const link = document.createElement('a');
    link.href = window.URL.createObjectURL(csvData);
    link.setAttribute('download', 'products.csv');
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
  }
}